The non-structural protein 5(NS5)is a highly conserved protein in the Flavivirus genus,acting as both a methyltransferase(MTase)and an RNA-dependent RNA polymerase(RdRp).It has been well documented that NS5 plays a crucial role in the replication of viral RNA.Recent studies have shown that NS5 proteins from different flaviviruses interact with various proteins in host cells,aiding the virus in evading the immune system.This review summarizes the structure,subcellular localization,and function of NS5 proteins.Additionally,we outline how flavivirus NS5 proteins contribute to viral replication and immune evasion.Lastly,we present the recent developments of specific small molecule inhibitors that target NS5 proteins.

Objective To investigate the infection status and changing trend of hepatitis C virus(HCV)infection in hospitalized patients in medical institutions,and provide reference for formulating HCV infection prevention and control strategies.Methods HCV infection surveillance results from cross-sectional survey data reported to China Healthcare-associated Infection(HAI)Surveillance System in 2020 were summarized and analyzed,HCV positive was serum anti-HCV positive or HCV RNA positive,survey result was compared with the survey results from 2003.Results In 2020,1 071 368 inpatients in 1 573 hospitals were surveyed,738 535 of whom underwent HCV test,4 014 patients were infected with HCV,with a detection rate of 68.93％and a HCV positive rate of 0.54％.The positive rate of HCV in male and female patients were 0.60％and 0.48％,respectively,with a statistically sig-nificant difference(x2=47.18,P＜0.001).The HCV positive rate in the 50-＜60 age group was the highest(0.76％),followed by the 40-＜50 age group(0.71％).Difference among all age groups was statistically signifi-cant(x2=696.74,P＜0.001).In 2003,91 113 inpatients were surveyed.35 145 of whom underwent HCV test,resulting in a detection rate of 38.57％;775 patients were infected with HCV,with a positive rate of 2.21％.In 2020,HCV positive rates in hospitals of different scales were 0.46％-0.63％,with the highest in hospital with bed numbers ranging 600-899.Patients'HCV positive rates in hospitals of different scales was statistically signifi-cant(X2=35.34,P＜0.001).In 2020,12 provinces/municipalities had over 10 000 patients underwent HCV-rela-ted test,and HCV positive rates ranged 0.19％-0.81％,with the highest rate from Hainan Province.HCV posi-tive rates in different departments were 0.06％-0.82％,with the lowest positive rate in the department of pedia-trics and the highest in the department of internal medicine.In 2003 and 2020,HCV positive rates in the depart-ment of infectious diseases were the highest,being 7.95％and 3.48％,respectively.Followed by departments of orthopedics(7.72％),gastroenterology(3.77％),nephrology(3.57％)and general intensive care unit(ICU,3.10％)in 2003,as well as departments of gastroenterology(1.35％),nephrology(1.18％),endocrinology(0.91％),and general intensive care unit(ICU,0.79％)in 2020.Conclusion Compared with 2003,HCV positive rate decreased significantly in 2020.HCV infected patients were mainly from the department of infectious diseases,followed by departments of gastroenterology,nephrology and general ICU.HCV infection positive rate varies with gender,age,and region.

Objective To observe the effectiveness of fluorescence labeling-based assay bundle intervention in the prevention and control of multidrug-resistant organism(MDRO)infection.Methods Patients who were detected MDRO in a hospital from January to December 2022 were selected as the research subjects.MDRO monitoring data and implementation status of prevention and control measures were collected.Fluorescence labeling assay was adopted to monitor the cleaning and disinfection effectiveness of the surrounding object surface of the bed units.Based on the bundled prevention and control measures as well as management mode of the pre-intervention group,the post-intervention group implemented enhanced rectification measures for the problems found by the pre-interven-tion group.Changes in relevant indicators between January-June 2022(before intervention)and July-December 2022(after intervention)were compared.Results There were 136 MDRO-infected patients in the pre-intervention group,208 MDRO strains were detected and 10 healthcare-associated infection(HAI)occurred.There were 128 MDRO-infected patients in the post-intervention group,198 MDRO strains were detected and 9 HAI occurred.Af-ter intervention,the total detection rates of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-re-sistant Acinetobacter baumannii(CRAB),and total MDRO from patients decreased significantly compared to before intervention(all P＜0.05).After intervention,the detection rates of MRSA,carbapenem-resistant Pseudomonas aeruginosa(CRPA),CRAB,and total MDRO from the surrounding object surface were all lower than those before intervention(all P＜0.05).The detection rate of MDRO from surrounding object surface before intervention was 34.52％,which showed a decreased trend after intervention(P＜0.05).The clearance rate of fluorescent labeled markers before intervention was 41.84％,which showed an upward trend after implementing intervention measures(from July to December),and increased to 85.00％at the end of intervention(November-December).The comp-liance rates of issuing isolation medical orders,placing isolation labels,using medical supplies exclusively,and cor-rectly handling medical waste after intervention have all increased compared to before intervention(all P＜0.05).Conclusion Adopting fluorescence labeling-based assay bundle intervention can effectively improve the effectiveness of MDRO infection prevention and control.

Objective To investigate the epidemiological characteristics of foodborne diseases in Liuzhou City, and to provide reference for formulating the prevention and control measures of foodborne diseases. Methods The surveillance data of foodborne diseases in 25 sentinel hospitals in Liuzhou City from 2018 to 2020 were collected for statistical analysis. Results From 2018 to 2020, a total of 9 317 cases of foodborne diseases were reported in Liuzhou City, and 2 158 samples were collected for pathogen detection. A total of 311 cases were detected positive , with a detection rate of 14.41%. Norovirus had the highest detection rate (8.63%), followed by Salmonella (4.08%) and Escherichia coli (3.10%). July to October was a period of high incidence of foodborne disease（ 41.17%）. The proportion of patients aged 60 and over was the highest (18.49%), followed by the age group of 30-39 (18.03%). Suspicious foods were mainly meat and meat products (22.35%) and aquatic animals and their products (13.89%). The suspicious eating places were mainly families (40.43%) and restaurants (13.63%). Conclusion The high incidence of foodborne diseases in Liuzhou occurs in summer and autumn. The main pathogens are Salmonella and norovirus. Infected patients are concentrated in the age group of 60 years and above and the age group of 30 to 39 years old. The family is the main place of foodborne disease, followed by the restaurants and hotels. Suspicious foods include mainly meat and meat products and aquatic animals and their products. It is necessary to strengthen monitoring ability and food safety education to reduce the occurrence of foodborne diseases.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant solid tumor of the digestive system, characterized by rapid progression and difficulties of early diagnosis. Five-year survival rate of the patients is less than 9%. With the acceleration of global population aging and lifestyle change, the incidence of PDAC has been increasing annually. Currently, surgical treatment and chemotherapy remain the standard treatment options for PDAC patients. Early symptoms of PDAC are so undetectable that most patients miss the optimal opportunity for radical surgical resection. Even among those who undergo surgery, the high recurrence rate remains a major problem. PDAC is known for its unique tumor microenvironment. The cellular and non-cellular components in the tumor microenvironment account for as much as 90% of the tumor stroma, presenting many potential targets for PDAC therapy. Activated pancreatic stellate cells within PDAC tissue express specific proteins and secrete various cytokines and metabolites, which directly contribute to the proliferation, invasion, and metastasis of PDAC cells. These elements are critical in extracellular matrix production, connective tissue hyperplasia, immune tolerance, and drug resistance. Immune cells, such as macrophages and neutrophils, exert immunosuppressive and tumor-promoting roles in PDAC progression. The extracellular matrix, which serve as a natural physical barrier, induces interstitial hypertension and reduces blood supply, thereby hindering the delivery of drugs to the tumor. Additionally, it helps the metastasis and differentiation of PDAC cells, reducing the efficacy of clinical chemotherapy and immunotherapy. Although chemotherapeutic agents like gemcitabine have been used in the clinical treatment of PDAC for more than 20 years, the curative effect is obstructed by their poor stability in the bloodstream, low cellular uptake, and poor targeting. While small-molecule inhibitors targeting mutations such as KRAS^G12C, BRCA, and NTRK fusion have shown great potential for molecular targeted treatments and gene therapies of PDAC, their broader application is limited by side effects and restricted scope of patients. The advancement of nanotechnology brings new strategies for PDAC treatment. By virtue of unique size characteristics and actual versatility, different drug-delivery nanosystems contribute to overcome the dense stromal barrier, prolong the circulation time of therapeutics and realize precise PDAC treatment by targeted drug delivery. Clinical nanodrugs such as albumin-bound paclitaxel (nab-paclitaxel) and irinotecan liposome greatly improve the pharmacokinetics of conventional chemotherapeutics and promote drug accumulation inside the tumor, thereby are applying to the first-line treatment of PDAC. It is noteworthy that none nanodrugs with active targeting design have been approved for clinical treatment yet, though many are in clinical trials. In this review, we discuss promising targeting strategies based on different nanodrug delivery systems for treatment of PDAC. One major nanostrategy focuses on the tumor cell targeting and its applications in chemotherapy, molecular targeting therapy, gene therapy, and immunotherapy of PDAC. Another nanostrategy targets the tumor microenvironment, which highlights the nanosystems specifically regulating pancreatic stellate cells, immune cells and the extracellular matrix. Recent progress of developing new nanotheraputics for breakthrough in the fight of PDAC are elaborated in this review. We also provide our perspectives on the challenges and opportunities in the field.

To explore the absorption mechanism of APS-Ⅱ in vivo by establishing M cell model. First, Astragalus polysaccharides (APS) was divided into two different molecular weight polysaccharides APS-I ( > 2 000 kDa) and APS-II (10 kDa) by ultrafiltration, and APS-II (10 kDa) was prepared and fluorescently labeled. Meanwhile, M cell model was constructed by Caco-2 cells and Raji cells. The M cell model was treated with transport inhibitors to explore the transport of APS-Ⅱ on M cells. The results show that FITC has been successfully labeled to the end of APS-Ⅱ, and the M cell model was successfully constructed, which found that APS-Ⅱ could be transported by M cells, and four transport inhibitors of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), genistein, dynasore and nocodazole indicated that APS-II may enter cells through clathrin and caveolin-mediated endocytosis.

italic>Astragalus polysaccharides are the most immunoregulatory active and abundant substances in Astragalus, with anti-tumor, anti-viral, and immune-promoting biological activities. They have been widely used in clinical practice. Previous studies have found that Astragalus polysaccharides are mainly composed of two different polysaccharides, APS-I (>2 000 kDa) and APS-Ⅱ (10 kDa), with APS-Ⅱ (10 kDa) being the most active component of Astragalus polysaccharides. We used α-1,4-glucan endo-hydrolysis enzyme to degrade APS-Ⅱ into oligosaccharides, and screened the immune activity of oligosaccharides in vitro. We found that the overall immune activity of 2-9 oligosaccharides was low, while the immune activity of 10-14 oligosaccharides was strong, and the activity was better than that of untreated APS-Ⅱ. To investigate the key structural features of APS-Ⅱ oligosaccharides that play a role in immune activity, we used MALDI-TOF-MS biochemical mass spectrometry and high-resolution mass spectrometry instrument ESI-Q Exactive-MS to analyze the APS enzymatic oligosaccharides. By comparing, we found that 10-14 oligosaccharides contain 1→4 and 1→6 branched structures with coexisting linkages, suggesting that 1→4 and 1→6 linkages in branched structures are key structural features that play a role in the immune activity of APS-Ⅱ, laying a theoretical foundation for the structure-activity relationship of Astragalus polysaccharides and oligosaccharides.

Objective To investigate changes in the urinary metabolite profiles of children exposed to polycyclic aromatic hydrocarbons(PAHs)during critical brain development and explore their potential link with the intestinal microbiota. Methods Liquid chromatography-tandem mass spectrometry was used to determine ten hydroxyl metabolites of PAHs(OH-PAHs)in 36-month-old children.Subsequently,37 children were categorized into low-and high-exposure groups based on the sum of the ten OH-PAHs.Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to identify non-targeted metabolites in the urine samples.Furthermore,fecal flora abundance was assessed by 16S rRNA gene sequencing using Illumina MiSeq. Results The concentrations of 21 metabolites were significantly higher in the high exposure group than in the low exposure group(variable importance for projection>1,P<0.05).Most of these metabolites were positively correlated with the hydroxyl metabolites of naphthalene,fluorine,and phenanthrene(r=0.336-0.531).The identified differential metabolites primarily belonged to pathways associated with inflammation or proinflammatory states,including amino acid,lipid,and nucleotide metabolism.Additionally,these distinct metabolites were significantly associated with specific intestinal flora abundances(r=0.34-0.55),which were mainly involved in neurodevelopment. Conclusion Higher PAH exposure in young children affected metabolic homeostasis,particularly that of certain gut microbiota-derived metabolites.Further investigation is needed to explore the potential influence of PAHs on the gut microbiota and their possible association with neurodevelopmental outcomes.

Objective To explore the key targets and signaling pathways in the therapeutic mechanism of Semiliquidambar cathayensis Chang(SC)root against pancreatic cancer network pharmacology and molecular docking studies and cell experiments.Methods The targets of SC and pancreatic cancer were predicted using the network pharmacological database,the protein-protein interaction network was constructed,and pathways,functional enrichment and molecular docking analyses were performed.CCK-8 assay was used to test the inhibitory effect of the aqueous extract of SC root on 8 cancer cell lines,and its effects on invasion,migration,proliferation,and apoptosis of pancreatic cancer cells were evaluated.Western blotting was performed to verify the results of network pharmacology analysis.Results We identified a total of 18 active components in SC,which regulated 21 potential key targets in pancreatic cancer.GO and KEGG pathway enrichment analyses showed that these targets were involved mainly in the biological processes including protein phosphorylation,signal transduction,and apoptosis and participated in cancer signaling and PI3K-Akt signaling pathways.Among the 8 cancer cell lines,The aqueous extract of SC root produced the most obvious inhibitory effect in pancreatic cancer cells,and significantly inhibited the invasion,migration,and proliferation and promoted apoptosis of pancreatic cancer Panc-1 cells(P<0.05).Western blotting confirmed that SC significantly inhibited the phosphorylation levels of PI3K and AKT in Panc-1 cells(P<0.001).Conclusion The therapeutic effect of SC root against pancreatic cancer effects is mediated by its multiple components that act on different targets and pathways including the PI3K-Akt pathway.

Bacterial biofilms gave rise to persistent infections and multi-organ failure, thereby posing a serious threat to human health. Biofilms were formed by cross-linking of hydrophobic extracellular polymeric substances (EPS), such as proteins, polysaccharides, and eDNA, which were synthesized by bacteria themselves after adhesion and colonization on biological surfaces. They had the characteristics of dense structure, high adhesiveness and low drug permeability, and had been found in many human organs or tissues, such as the brain, heart, liver, spleen, lungs, kidneys, gastrointestinal tract, and skeleton. By releasing pro-inflammatory bacterial metabolites including endotoxins, exotoxins and interleukin, biofilms stimulated the body’s immune system to secrete inflammatory factors. These factors triggered local inflammation and chronic infections. Those were the key reason for the failure of traditional clinical drug therapy for infectious diseases.In order to cope with the increasingly severe drug-resistant infections, it was urgent to develop new therapeutic strategies for bacterial-biofilm eradication and anti-bacterial infections. Based on the nanoscale structure and biocompatible activity, nanobiomaterials had the advantages of specific targeting, intelligent delivery, high drug loading and low toxicity, which could realize efficient intervention and precise treatment of drug-resistant bacterial biofilms. This paper highlighted multiple strategies of biofilms eradication based on nanobiomaterials. For example, nanobiomaterials combined with EPS degrading enzymes could be used for targeted hydrolysis of bacterial biofilms, and effectively increased the drug enrichment within biofilms. By loading quorum sensing inhibitors, nanotechnology was also an effective strategy for eradicating bacterial biofilms and recovering the infectious symptoms. Nanobiomaterials could intervene the bacterial metabolism and break the bacterial survival homeostasis by blocking the uptake of nutrients. Moreover, energy-driven micro-nano robotics had shown excellent performance in active delivery and biofilm eradication. Micro-nano robots could penetrate physiological barriers by exogenous or endogenous driving modes such as by biological or chemical methods, ultrasound, and magnetic field, and deliver drugs to the infection sites accurately. Achieving this using conventional drugs was difficult. Overall, the paper described the biological properties and drug-resistant molecular mechanisms of bacterial biofilms, and highlighted therapeutic strategies from different perspectives by nanobiomaterials, such as dispersing bacterial mature biofilms, blocking quorum sensing, inhibiting bacterial metabolism, and energy driving penetration. In addition, we presented the key challenges still faced by nanobiomaterials in combating bacterial biofilm infections. Firstly, the dense structure of EPS caused biofilms spatial heterogeneity and metabolic heterogeneity, which created exacting requirements for the design, construction and preparation process of nanobiomaterials. Secondly, biofilm disruption carried the risk of spread and infection the pathogenic bacteria, which might lead to other infections. Finally, we emphasized the role of nanobiomaterials in the development trends and translational prospects in biofilm treatment.